gettimeofday: port recent C++ fix to Emacs

[gnulib.git] / lib / open.c

diff --git a/lib/open.c b/lib/open.c
index 97c30ce..a0c43ea 100644 (file)
--- a/lib/open.c
+++ b/lib/open.c
@@ -1,5 +1,5 @@
 /* Open a descriptor to a file.
-   Copyright (C) 2007-2008 Free Software Foundation, Inc.
+   Copyright (C) 2007-2013 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -16,23 +16,41 @@
 
 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
 
+/* If the user's config.h happens to include <fcntl.h>, let it include only
+   the system's <fcntl.h> here, so that orig_open doesn't recurse to
+   rpl_open.  */
+#define __need_system_fcntl_h
 #include <config.h>
 
-/* Specification.  */
+/* Get the original definition of open.  It might be defined as a macro.  */
 #include <fcntl.h>
+#include <sys/types.h>
+#undef __need_system_fcntl_h
 
-/* If the fchdir replacement is used, open() is defined in fchdir.c.  */
-#ifndef FCHDIR_REPLACEMENT
+static int
+orig_open (const char *filename, int flags, mode_t mode)
+{
+  return open (filename, flags, mode);
+}
 
-# include <errno.h>
-# include <stdarg.h>
-# include <string.h>
-# include <sys/types.h>
-# include <sys/stat.h>
+/* Specification.  */
+/* Write "fcntl.h" here, not <fcntl.h>, otherwise OSF/1 5.1 DTK cc eliminates
+   this include because of the preliminary #include <fcntl.h> above.  */
+#include "fcntl.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifndef REPLACE_OPEN_DIRECTORY
+# define REPLACE_OPEN_DIRECTORY 0
+#endif
 
 int
 open (const char *filename, int flags, ...)
-# undef open
 {
   mode_t mode;
   int fd;
@@ -43,22 +61,28 @@ open (const char *filename, int flags, ...)
       va_list arg;
       va_start (arg, flags);
 
-      /* If mode_t is narrower than int, use the promoted type (int),
-        not mode_t.  Use sizeof to guess whether mode_t is narrower;
-        we don't know of any practical counterexamples.  */
-      mode = (sizeof (mode_t) < sizeof (int)
-             ? va_arg (arg, int)
-             : va_arg (arg, mode_t));
+      /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+         creates crashing code when 'mode_t' is smaller than 'int'.  */
+      mode = va_arg (arg, PROMOTED_MODE_T);
 
       va_end (arg);
     }
 
-# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+#if GNULIB_defined_O_NONBLOCK
+  /* The only known platform that lacks O_NONBLOCK is mingw, but it
+     also lacks named pipes and Unix sockets, which are the only two
+     file types that require non-blocking handling in open().
+     Therefore, it is safe to ignore O_NONBLOCK here.  It is handy
+     that mingw also lacks openat(), so that is also covered here.  */
+  flags &= ~O_NONBLOCK;
+#endif
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
   if (strcmp (filename, "/dev/null") == 0)
     filename = "NUL";
-# endif
+#endif
 
-# if OPEN_TRAILING_SLASH_BUG
+#if OPEN_TRAILING_SLASH_BUG
   /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
      is specified, then fail.
      Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
@@ -84,16 +108,40 @@ open (const char *filename, int flags, ...)
     {
       size_t len = strlen (filename);
       if (len > 0 && filename[len - 1] == '/')
-       {
-         errno = EISDIR;
-         return -1;
-       }
+        {
+          errno = EISDIR;
+          return -1;
+        }
     }
-# endif
+#endif
 
-  fd = open (filename, flags, mode);
+  fd = orig_open (filename, flags, mode);
+
+#if REPLACE_FCHDIR
+  /* Implementing fchdir and fdopendir requires the ability to open a
+     directory file descriptor.  If open doesn't support that (as on
+     mingw), we use a dummy file that behaves the same as directories
+     on Linux (ie. always reports EOF on attempts to read()), and
+     override fstat() in fchdir.c to hide the fact that we have a
+     dummy.  */
+  if (REPLACE_OPEN_DIRECTORY && fd < 0 && errno == EACCES
+      && ((flags & O_ACCMODE) == O_RDONLY
+          || (O_SEARCH != O_RDONLY && (flags & O_ACCMODE) == O_SEARCH)))
+    {
+      struct stat statbuf;
+      if (stat (filename, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))
+        {
+          /* Maximum recursion depth of 1.  */
+          fd = open ("/dev/null", flags, mode);
+          if (0 <= fd)
+            fd = _gl_register_fd (fd, filename);
+        }
+      else
+        errno = EACCES;
+    }
+#endif
 
-# if OPEN_TRAILING_SLASH_BUG
+#if OPEN_TRAILING_SLASH_BUG
   /* If the filename ends in a slash and fd does not refer to a directory,
      then fail.
      Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
@@ -108,21 +156,26 @@ open (const char *filename, int flags, ...)
      with ENOTDIR.  */
   if (fd >= 0)
     {
+      /* We know len is positive, since open did not fail with ENOENT.  */
       size_t len = strlen (filename);
-      if (len > 0 && filename[len - 1] == '/')
-       {
-         struct stat statbuf;
-
-         if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
-           {
-             close (fd);
-             errno = ENOTDIR;
-             return -1;
-           }
-       }
+      if (filename[len - 1] == '/')
+        {
+          struct stat statbuf;
+
+          if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
+            {
+              close (fd);
+              errno = ENOTDIR;
+              return -1;
+            }
+        }
     }
-# endif
+#endif
+
+#if REPLACE_FCHDIR
+  if (!REPLACE_OPEN_DIRECTORY && 0 <= fd)
+    fd = _gl_register_fd (fd, filename);
+#endif
 
   return fd;
 }
-#endif